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IBM mainframe computer disc drives in the 1980's (can't speak for >1990's) always used liquid cooling.
Late 80's (88-89) the 3380's we had were air cooled (i'm fairly sure), certainly the 3390's were.
Then in 92 we threw all the IBM DASD out and got HDS - much better I remember the room full of chillers for the TCM coolant on the 3084's & 3090's.
You may well be right and my memory is playing tricks with me.
We had a dual machine system with an IBM 3090 and an Amdahl 5850(?), so maybe it was the IBM processor rather than the disc drives that were liquid cooled, seem to recall that the Amdahl was air cooled.